Field of the Invention
The present invention relates to wireless communication.
Related Art
3rd generation partnership project (3GPP) long term evolution (LTE) evolved from a universal mobile telecommunications system (UMTS) is introduced as the 3GPP release 8. The 3GPP LTE uses orthogonal frequency division multiple access (OFDMA) in a downlink, and uses single carrier-frequency division multiple access (SC-FDMA) in an uplink. The 3GPP LTE employs multiple input multiple output (MIMO) having up to four antennas. In recent years, there is an ongoing discussion on 3GPP LTE-advanced (LTE-A) evolved from the 3GPP LTE.
As disclosed in 3GPP TS 36.211 V10.4.0 (2011-12) “Evolved Universal Terrestrial Radio Access (E-UTRA); Physical Channels and Modulation (Release 10)”, 3GPP LTE/LTE-A may divide the physical channel into a downlink channel, i.e., a physical downlink shared channel (PDSCH) and a physical downlink control channel (PDCCH), and an uplink channel, i.e., a physical uplink shared channel (PUSCH) and a physical uplink control channel (PUCCH).
In recent years, machine-type communication (MTC), which is communication between devices or between a device and a server via no human interaction, that is, without human intervention, is actively under research. MTC refers to the concept of communication based on an existing wireless communication network performed by a machine device instead of a user equipment (UE) used by a user.
Since MTC has a feature different from communication of a normal UE, a service optimized to MTC may differ from a service optimized to human-to-human communication. In comparison with a current mobile network communication service, MTC can be characterized as a different market scenario, data communication, less costs and efforts, a potentially great number of MTC devices, wide service areas, low traffic for each MTC device, etc.
Recently, it is considered to extend cell coverage of a BS for an MTC device, and various schemes for extending the cell coverage are under discussion. However, when the cell coverage is extended, if the BS transmits a channel to the MTC device located in the coverage extension region as if transmitting a channel to a normal UE, the MTC device has a difficulty in receiving the channel.
Further, as the MTC device is expected to have low performance in order to supply more MTC devices at a low price, if the BS transmits a PDCCH, an EPDCCH, or a PDSCH to the MTC apparatus located in the coverage extension region as if transmitting a PDCCH, an EPDCCH, or a PDSCH to a normal UE, the MTC device has a difficulty in receiving the PDCCH, an EPDCCH, or the PDSCH.